E21 323i M20 Motor Swap

The original M20B23 in my new 1980 323i had a serious problem - it was burning a scary amount of oil. I spent some time getting it to run better but gave up when the fuel adjustment screw became cross-threaded in the AFM. I had a stroker M20 under way already so pulling the original 2.3L was always the plan anyway.

I've never pulled an engine by myself before. I have assisted a few times and I've done just about everything else. On more modern BMWs the engine and transmission can be separated and the engine removed on its own. But the driveshaft on my 1980 car does not separate easily. So I removed the transmission still attached to the engine. It was pretty easy.

I used a standard engine hoist with a chain connected to the main lift point on the front of the cylinder head. And I supported the back of the transmission with my floor jack. The engine came out hanging downward and there was enough room to clear the nose.

step 2.
it was about this time that I realized the speedometer drive cable was still attached to the transmission.

step 3

in its new home!

E21 to E30 wiring

E21 to E30 wiring

wiring harness #2. the first was very rough with the wrong connectors. this one will the final one but I left the harness insulation and the main connectors off until I was sure everything was hooked up correctly.

Alternator ground.

E36 junction block. Top wire goes to starter. Middle wires go to coil. Bottom wires are the power from the battery.

New G17 ground.

E30 > E21 fuse box plug

Wiring harness at the fuse box.

E30 > E21 fuse box plug

Wiring harness at the C101 connector. There are only 7 connections!

Wiring harness at the C101 connector.

E30 C101 connector in place.

The green/violet wire runs from this relay to the green/black wire that powers the fuel pump.